Gonna be pedantic/crotchety about this because I got into advanced math classes but it was my brother who got the 84+ (I had to settle for a 83+). Guess who's the engineer now, and who's the NEET? Your kids pay attention to what (who) you value, folks.
And it sure would be funny if the calculator was a one-off instead of just one instance in a pattern of dysfunctional parenting that taught:
Son 1: The family will always have your back, no matter the outcome as; you'll be rewarded, so long as you try.
Son 2: No matter what you accomplish, you will be valued less.
Real laugh-riot there. Hope that clears things up.
I had a TI-85 (maybe 86), unlike the entire rest of my school who had 83s.
There was a difference: when programming in TI-Basic, variable names on a TI-83 are limited to a single character. On the 85, you can make them longer.
But that was pretty much the only difference, and it will never come up if you're using the calculator for school-related reasons.
(For calculus, I had an 89. The differences are much more significant there.)
I also was the one person with a TI-85 in a school of 83s. But by the time I took the statistics class I knew enough BASIC to write my own programs to replicate the functionality that was missing.
Reason : making due with more scarcity increased independence and critical thinking.
I don't know if that was your point...
No, I was too scared to ask.